Short answer
Marble is limestone or dolomite recrystallised by heat and pressure; the pure calcite is white, and veins are where impurities — clay, sand, iron oxides, chert, serpentine — were concentrated and redistributed. Calcite's modest refractive index lets light penetrate before scattering out, which gives marble its glow. The same calcite dissolves in acids, so drips of lemon juice or wine leave dull etch marks, and iron or absorbed organics can turn it yellow or rusty over time.
Relative to other materials in this section, not a measurement of a particular product.
| Process | What you see | Driven by | Slowing it |
|---|---|---|---|
| Acid etching | Dull, pale marks on polished surfaces | Acids (citrus, wine, acid rain, some cleaners) dissolving calcite | Neutral cleaners; re-hone and polish; honed finish hides etching |
| Staining and yellowing | Rust-coloured or yellow patches | Iron in the stone or from fixings; absorbed oils and organics | Poultices; impregnating sealers; stainless fixings |
Marble forms when limestone or dolomite is metamorphosed: the original grains recrystallise into an interlocking mosaic of calcite or dolomite. Very clean starting rock gives pure white marbles such as statuary Carrara. Anything else in the original sediment is squeezed, folded and concentrated during metamorphism into veins, clouds and swirls: iron oxides give gold, pink and red; clay and organic matter give greys; chert gives pale streaks; magnesium-rich marbles can grow serpentine and turn green. Because the veining records deformation, it can change direction across a block, and bookmatching — opening consecutive slices like a book — is used to make patterns symmetrical across a wall or worktop.
Unlike most opaque stones, marble is translucent. Light enters the surface, travels through calcite crystals and scatters back out some distance away, rather than bouncing off the face. Reference sources put the penetration at the order of a centimetre or more for fine white marbles, which is why sculptors valued it for skin, why marble statues look softer than plaster casts, and why thin white marble lit from behind glows warm. It also means the surface colour depends slightly on what is under it — adhesive colour and background matter for thin tiles — and that fine carved detail reads a little blurred, as light diffuses sideways under the surface.
Calcite reacts with acids and dissolves, giving off carbon dioxide. On a polished marble surface even a mild acid — citrus juice, wine, vinegar, some bathroom cleaners — removes the polish where it sits, leaving a dull, paler mark that looks like a stain but is actually a change in gloss. Honed marble shows these marks far less because it is already matt. Outdoors, slightly acidic rain slowly erodes exposed marble, rounding carving and roughening the surface, and the roughened face scatters more light so the stone looks whiter and chalkier; in polluted areas, sheltered zones accumulate dark gypsum crusts. Re-polishing restores etched surfaces; sealers reduce staining but do not stop etching.
White marble can yellow for several reasons. Some marbles contain finely dispersed iron minerals that oxidise when wet — a risk with wet-installed tiles and with steam — producing yellow to rusty tones. Iron fixings and wire in older installations rust and bleed. Porous marble absorbs oils, cosmetics, tannins from tea and coffee, and old waxes that yellow with age. Copper and bronze fittings leave green stains. Each has a different remedy — specialist poultices draw out absorbed stains, iron-specific treatments reduce rust — so identifying the cause matters before cleaning, and strong acidic or alkaline cleaners generally make things worse.
Why: Acid etching of the calcite, removing the polish.
Fix: Re-hone and polish the area; consider a honed finish for kitchens.
Why: Iron minerals oxidising after wet installation or cleaning, or absorbed organics.
Fix: Identify the cause; iron-specific or organic poultices; minimise water.
Why: Adhesive colour and uneven bedding showing through translucent stone.
Fix: White adhesive with full coverage.
Each statement is labelled by kind — established fact, a standard’s requirement, observed market data, a convention, or Colourwise’s own interpretation or analysis — with the strength of the evidence behind it.
FactModerate evidence
Marble consists mostly of calcite or dolomite; pure white marble arises from very clean limestone or dolomite, and its veining comes from impurities such as clay, sand, iron oxides or chert, with serpentine giving green tones.
Source: Marble
FactStrong evidence
Light penetrates some distance into marble before it scatters back out, a subsurface-scattering effect that gives marble its soft, waxy appearance.
Source: Marble; A practical model for subsurface light transport (SIGGRAPH 2001)
FactStrong evidence
Acid rain damages materials containing calcium carbonate such as marble, causing surface loss and erosion.
Source: Preservation Brief 48: Preserving Grave Markers in Historic Cemeteries
FactModerate evidence
Pollutant gases turn exposed bronze surfaces into water-soluble minerals that rain carries down onto masonry below, disfiguring stone plinths and pedestals.
Source: Preservation Brief 48: Preserving Grave Markers in Historic Cemeteries
Reviewed 29 September 2026. Colourwise summarises its sources in its own words and does not reproduce standards text or proprietary colour data. Spotted an error? Tell us.